The Dalai Lama has endorsed the pope’s radical message on climate change and called on fellow religious leaders to “speak out about current affairs which affect the future of mankind”.

The spiritual Buddhist leader was speaking at Glastonbury festival on a panel discussing issues of global warming alongside Katharine Viner, the Guardian’s editor, and the Guardian columnist George Monbiot.

He praised the pope’s recent encyclical on climate change, which warned of the unprecedented destruction of ecosystems, adding that it was the duty of people to “say more – we have to make more of an effort, including demonstrations”.

The Dalai Lama, who will turn 80 next Monday, called for more pressure to be put on international governments to stop the burning of fossil fuels and mass deforestation and invest more in green energy sources.

He said: “The concept of war is outdated, but we do need to fight. Countries think about their own national interest rather than global interests and that needs to change because the environment is a global issue.

“It is not sufficient to just express views, we must set a timetable for change in the next two to four years.”

The Dalai Lama said individuals also had their own responsibility towards the planet. Speaking about his own efforts, he said he always turned the lights off when leaving rooms and took showers instead of baths – though he admitted taking two showers a day.

The Tibetan leader went on to call for countries including Russia and the US to scrap their nuclear weapons and criticised Vladimir Putin, the Russian president, for his recent threat to increase the country’s nuclear arsenal.

Monbiot took the opportunity to appeal to Glastonbury to go further with its efforts to be ecologically friendly. He asked: “Why aren’t we calling for Glastonbury to be meat-free and fish-free?”

The Dalai Lama also embraced his historic visit to Glastonbury on Sunday with several other appearances, including an early gathering at the hallowed ground of the Stone Circle.

Speaking from a modest wooden stage emblazoned with the Tibetan flag, he made a rare comment on the escalating conflict in the Middle East, describing Islamic State violence in Syria and Iraq as “unthinkable”.

In a speech before hundreds of rain-soaked campers, the Dalai Lama said: “In this very moment, in some parts of the world, like Syria, Iraq, Nigeria and some other places – they’re killing, human to human being. Unthinkable. And the worst thing [is that] conflict, killing each other, in the name of their faith.”

He said the real meaning of jihad was not harming others, but using constructive emotion to combat destructive emotions. He said: “I daily use it in my five hours of meditation, this kind of jihad.

“There is nothing wrong with religious beliefs, but the people who are supposed to be following the religion have a lack of moral principle, lack of conviction.’

Asked later whether music made him happy, the Dalai Lama said “not much”. He said he challenged the view that music could bring inner peace: “If music really brings inner peace, then this Syria and Iraq – killing each other – there through some strong music can they reduce their anger? I don’t think so.”

The Tibetan leader made his final appearance at the festival during Patti Smith’s afternoon set on the Pyramid Stage, where he was presented with a birthday cake while Smith led the crowd in a rousing chorus of Happy Birthday. She then read a little birthday poem in his honour.

Speaking to Smith and her fellow musicians on stage, the Dalai Lama said: “Most of you have white hair – but the voice and the physical action looks very youthful. So that gives me encouragement myself. I’m now 80, but I should be more active like you.”

Indeed, his numerous appearances proved to be some of the most talked-about events over the weekend. During the his first Stone Circle speech, a Tibetan man, clutching a giant flag of his home country, said he had bought a Glastonbury ticket just to see the Dalai Lama and travelled through the night to get to Worthy Farm in time for his appearance.

“I’m very, very excited. It means a lot to hear him speak. We drove from 2 o’clock last night, it took a long time. The whole night I couldn’t sleep. It is very exciting to be here,” he said, declining to be named because he feared repercussions from the Chinese authorities.

Merle Hansen, who was also in the crowd, said the Dalai Lama’s appearance was one of the highlights in more than 30 years of coming to Glastonbury.

She said: “I thought it was great, absolutely wonderful and perfect timing. It’s so nice to see so many people here – I find it very touching and moving.”